Hello, Gurus: I tried to test if the sample mean of a dataset is zero.
The data has 1500 numbers with a lot of zeros and some small positive numbers. The data range on [0,1] but the distribution is unknown. It is zero inflated anyway. I tried to use the Wilcoxon Signed Ranks test. But I read from this website that it does assume the population pdf is symmetric. http://www.cas.lancs.ac.uk/glossary_v1.1/nonparam.html#wsrt "The Wilcoxon Signed Ranks test does not require the assumption that the population is normally distributed. In many applications, this test is used in place of the one sample t-test<http://www.cas.lancs.ac.uk/glossary_v1.1/hyptest.html#1sampt>when the normality assumption is questionable. It is a more powerful alternative to the sign test, but does assume that the population probability distribution is symmetric." I wonder if wilcox.test( ) in R also assumes the symmetric pdf? I checked the sign test too. But "the sign *test* is not *testing equality*of population " If wilcox.test() cannot work for my data, I wonder if you could suggest a kind of test? I already tried t-test (assume normality) but I want to find something else. Many thanks! S [[alternative HTML version deleted]] ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
